control transformer question

[emahler]

we have a single phase air handler that is 240v. if it only received 1 leg (not 120v, just one leg) for about 4 hrs would it burn up the transformer and/or board?

 

[emahler]

add to this that there was no load, as the unit wasn't charged and the t-stats were off...

but i'm wondering if the small transformer wasn't 'single phased'...so to speak...

 

[augie47]

should not cause a problem. If the unit has no neutral the transformer should be 240v. the loss of one leg shoud stop all current flow.

 

[emahler]

that's what i was thinking...thanks

 

[kwired]

consider this scenario

consider this scenario

If you have this situation View attachment 4683 then you will have a reduced voltage applied to the transformer, how much will depend on the impedance of the transformer and the lighting load A that would be in series with the transformer with a total of 120 volts applied to the series circuit.

What kind of damage will or can that do depends on what is connected to the transformer and the voltage can further vary if there is enough present to actually pull in contactor to attempt to operate the blower.

 

[stevenj76]

No...

But you should look closer at the over current situation.

You see, alot of that Class 2 stuff is retrofitted into the old Class 3 pneumatic controls.

In other words, stuff that needs to be fused for 4A is still fused for 10A.


What line of controls??